The present invention relates generally to an automotive electronics control module enclosure (ECM hereafter). More specifically, the present invention relates to a die-cast automotive electronics control module enclosure with improved assembly characteristics.
Die-cast products are well known in the prior art. Die-casting forces molten metal, typically under high pressure, into metal dies in order to create formed components. The resulting products are typically accurately dimensioned, sharply defined, and allow for both smooth and textured surfaces. Additionally the dies may be formed to create unique and complex design configurations that may prove impossible or financially unviable for creation utilizing other manufacturing techniques. Although the use of die-casting techniques have been adopted by a variety of industries, one industry that has successfully utilized die-casting is the automotive industry.
Automotive designers have commonly looked to die-casting to form a variety of parts and elements for automotive manufacture. One genre of products in which die-casting has made significant inroads within the automotive industry is the area of electronic enclosures. These enclosures must often be formed with complex shapes to appropriately secure the electronic components mounted inside them. Additionally, the enclosures must provide adequate structural protection to prevent damage to the electronic component from the hostile automotive environment. Heat dissipation and electromagnetic compatibility can also play a role in dictating the enclosure""s configuration and material makeup. Die-casting allows each of the mentioned characteristics to be properly addressed while maintaining a low cost and flexible design process.
Although die-casting can be utilized to incorporate many structural features of an enclosure directly through the casting process, often features are machined or manufactured into the enclosure using post-die processes. Such is the case with present automotive electronics control module designs. Present automotive electronics control designs commonly utilize die-casting procedures to form the ECM housing (base) and sheet metal procedures to form the cover of enclosures. Adhesives may or may not be utilized to join the cover to the housing (base), and are sometimes used to provide an environmental seal to protect the electronics from automotive fluids. Additionally, screws are commonly used to secure the cover to the housing. Screws require either cored holes, or drilled holes in the die cast base in order to drive the screws through the clearance holes in the cover into the base enclosure. Typical problems with cored holes due to die cast tolerances include stripped holes from oversized holes, or unseated or broken screws from undersized holes. More die maintenance is required to assure properly sized holes due to the more rapid wearing of tool pins to form them. By utilizing a post die-casting procedure by drilling the holes, tighter tolerances can be achieved which help minimize scrap from stripped and/or unseated screws, however this is at additional cost due to the secondary operations required to the die cast. The use of screws also increases the cost of the enclosure due to the additional part cost of the screws, and the additional cost associated with handling and assembling the screws. Thus, although die-casting is utilized for general formation purposes, it is often combined with traditional manufacturing techniques that can serve to deplete the cost and time benefits provided by the die-casting.
In addition to the time and cost deficiencies associated with typical ECM enclosure manufacturing, present manufacturing techniques can add manufacturing concerns to the ECM enclosure. The drilling and driving of screws is capable of producing metal shavings that can find their way to the substrate or the connector cavity of the ECM. These metal shavings present a danger of creating electrical shorts and ECM malfunction, which is clearly unacceptable. Instead of screws, complex cover tab geometries may be utilized to form the edges of the cover over the base, thereby eliminating the concerns with screw usage. The complex cover tab geometry, however, is often associated with increased cover tooling costs and increased manufacturing costs associated with bending or clinching the tabs. The tab geometries on the cover also result in larger size covers to accommodate the tab geometry, thus resulting in higher material cost.
It would therefore be highly desirable to have an ECM enclosure that preserved the benefits associated with die-casting techniques, while improving upon the post casting manufacturing procedures usually required to assembly the ECM. Furthermore, it would be highly desirable to have an ECM enclosure that could be manufactured and assembled without the risks of electrical shorts associated with screw attachment methodologies.
It is, therefore, an object of the present invention to provide a die-cast ECM enclosure with improved assembly characteristics. It is a further object of the present invention to provide a die-cast ECM enclosure with reduced assembly costs.
In accordance with the objects of the present invention, an automotive electronics control module assembly is provided. The automotive electronics control module includes an automotive electronics control module enclosure housing an electrical component. The automotive electronics control module enclosure has a die-cast base portion including a plurality of die-cast post elements. The automotive electronics control module enclosure further includes a cover element having a plurality of cover holes. The plurality of die-cast post elements are positioned within the plurality of cover holes during assembly. The plurality of die-cast post elements are staked (plastically deformed, partially crushed) to secure the cover element to the base portion.